The threat of biological warfare has existed for centuries. By definition, biological warfare involves any deliberate use of disease to attack humans, plants, animals, or infrastructure. Biological weapons have been used only occasionally, but they have the potential to inflict great harm. Unlike the materials necessary to produce nuclear weapons, microorganisms, toxins, and viruses that are dangerous to human, animal, and plant life can be found abundantly in nature. The technology needed to turn these agents into weapons is less sophisticated than what is necessary to develop nuclear weapons. Furthermore, only a very small quantity of material is needed, much less than that needed to produce nuclear weapons, but could potentially cause a comparable death-toll.
Technology allows for some biological threat agents, which in their natural state pose only minimal dangers, to be genetically engineered into more threatening forms. Their availability in nature also changes, and science continues to discover new biological threat agents. The Center for Disease Control (CDC) and other agencies have compiled a list of the biological agents of greatest concern. They are segregated into categories, depending on a variety of factors.
Though the need to develop biological defense technologies to protect against the threat of terrorism is increasing, such biological defense technologies are hard to develop and test. Biological defense technologies are successful if they are able to detect the biological threat agent, inhibit biological threat agent contact with its host, inhibit biological threat agent growth, or kill the biological threat agent. Developing and testing biological defense technology in the presence of a biological threat agent poses serious hazards. Exposure of people working on defense technology, and/or the population at large, to a biological threat agent may result in serious injury or death. Methods allowing the safe development, testing, and training of biological defense technology are needed to minimize, or eliminate, the potential hazards associated with such technology development. However, the use of actual virulent threat agents is costly and risky. Furthermore, development and testing of technologies dealing with more than one threat agent face almost insurmountable difficulties in producing, storing, and employing more than one threat agent simultaneously.
The use of biological threat agents in the development, testing, and training of biological defense technology is impaired by safety issues, high cost, the need of special infrastructure and uncommon expertise. A simulant is an agent having biological and/or physical characteristics similar to a biological threat agent but when used in place of the biological threat agent is not harmful. Though the use of methods involving simulants is a good idea, very few simulants have been identified and are being used. In biodefense a few simulants, including spores of Bacillus subtilis (as surrogate of B. anthracis), Pantoea agglomerans (as surrogate of all vegetative threat bacteria) and the phage M13 (as surrogate of all threat viruses), are used in methods development, training, and testing and evaluation of biodefense countermeasures, and equipment. These simulants are totally inadequate to simulate threat agents on nucleic-acid based technologies, since B. subtilis, P. agglomerans, and M13 do not share genes with any of the actual threat agents that they are intended to mimic